The first arrangement: 3 large rooms+1 small room.
Arrange three large rooms, which can accommodate 3×6= 18, leaving 22- 18=4.
Arrange 1 small room, just enough for 4 people.
The second arrangement: 1 large room +3 small rooms.
Arrange 1 large room, which can accommodate 1×6=6, leaving 22-5= 16.
Arrange 4 small rooms, which can just accommodate 4×4= 16.
The third arrangement: 4 large rooms
4×6=24, that's enough.
The fourth arrangement: 6 small rooms
4×6=24, that's enough.